ozancicek commented on a change in pull request #24764: [SPARK-18570][ML][R] RFormula support * and ^ operators URL: https://github.com/apache/spark/pull/24764#discussion_r289753845
########## File path: mllib/src/main/scala/org/apache/spark/ml/feature/RFormulaParser.scala ########## @@ -144,10 +155,50 @@ private[ml] case class ResolvedRFormula( * R formula terms. See the R formula docs here for more information: * http://stat.ethz.ch/R-manual/R-patched/library/stats/html/formula.html */ -private[ml] sealed trait Term +private[ml] sealed trait Term { + + /** Default representation of a single Term as a part of summed terms. */ + def asTerms: Terms = Terms(Seq(this)) + + /** Creates a summation term by concatenation of terms. */ + def add(other: Term): Term = Terms(this.asTerms.terms ++ other.asTerms.terms) + + /** + * Fold by adding deletion terms to the left. Double negation + * doesn't cancel deletion in order not to add extra terms, e.g. + * a - (b - c) = a - Deletion(b) - Deletion(c) = a + */ + def subtract(other: Term): Term = { + other.asTerms.terms.foldLeft(this) { + case (left, right) => + right match { + case t: Deletion => left add t Review comment: ok, I got rid of those syntax ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
